Regarding Gizmodo a Netflix spokesman stated that the problem is that these older devices are running Windows Media DRM, a digital rights management service that has since been replaced by Microsoft PlayReady. Netflix has been using PlayReady since 2010 because it's easier to get content from movie studios and other providers in this format. Starting December 2, those older devices that can't upgrade to PlayReady will be blocked.
Affected devices include Roku SD (N1
The owners of these particular models also had problems with other services. Last year, Hulu announced that it would discontinue support for both VIZIO Smart TV with VIZIO Internet Apps and older Roku models. Older Roku devices can still access videos from Hulu's streaming library, but cannot access features like premium accessories or live television.